CN105423700A - Single-stage rectification equipment for separating air - Google Patents
Single-stage rectification equipment for separating air Download PDFInfo
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- CN105423700A CN105423700A CN201410455025.0A CN201410455025A CN105423700A CN 105423700 A CN105423700 A CN 105423700A CN 201410455025 A CN201410455025 A CN 201410455025A CN 105423700 A CN105423700 A CN 105423700A
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- heat exchanger
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04624—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using integrated mass and heat exchange, so-called non-adiabatic rectification, e.g. dephlegmator, reflux exchanger
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
- F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
- F25J3/04084—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of nitrogen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
- F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
- F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
- F25J3/04351—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
- F25J3/04357—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen and comprising a gas work expansion loop
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04642—Recovering noble gases from air
- F25J3/04648—Recovering noble gases from air argon
- F25J3/04654—Producing crude argon in a crude argon column
- F25J3/0466—Producing crude argon in a crude argon column as a parallel working rectification column or auxiliary column system in a single pressure main column system
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04642—Recovering noble gases from air
- F25J3/04648—Recovering noble gases from air argon
- F25J3/04721—Producing pure argon, e.g. recovered from a crude argon column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
Abstract
The invention belongs to the field of low-temperature rectification, relates to a method for preparing oxygen, nitrogen and argon by applying the principle of the low-temperature rectification to separate air, and provides a method for separating the air through single-stage rectification equipment. The method for separating the air through the single-stage rectification equipment is suitable for liquid equipment for mass preparation of a liquid oxygen product containing 99.5% of the oxygen, and meanwhile a pure nitrogen product containing 10 ppm-3 ppm of the oxygen can further be prepared. The method for separating the air through the single-stage rectification equipment has the advantages that a pure argon product can be prepared through an attached argon column, and the extraction efficiency of the oxygen, the nitrogen and the argon is very high; after impure nitrogen is circulated and compressed, the impure nitrogen is adopted as expanding gas; a pressure oxygen nitrogen product is prepared through compressed liquid oxygen and liquid oxygen inside a low-temperature liquid pump; the energy consumption of the equipment is very low, and the consumption of metallic materials is little.
Description
Technical field
The invention belongs to the field of cryogenic rectification air separation, the principle of application of cold temperature rectifying is separated air, produces the method for oxygen, nitrogen, argon.
Background technology
From Germany scientist in 1903 by throttling and twin-stage rectificating method, be born in the world since First oxygenerator, the development of air separation technology experienced by the course in a century the sixth of the twelve Earthly Branches; From the development history that a century is many, the pattern of traditional theory is not broken away from the development of air separation technology; In pressure column, the disappearance of stripping section is the basic reason of the empty point technical development of restriction, and in pressure column, the setting of stripping section is the developing direction of air separation technology.
Within 1903, Germany scientist woods German system has made First 10Nm3/h oxygenerator in the world, and it is obtained by throttling and twin-stage rectificating method; Within 1910, French liquid air company has manufactured First 50Nm3/h oxygenerator by Ke Laote round-robin method, and it is also obtained by twin-stage rectificating method; Nineteen thirty-nine Soviet scientists Ka Picha has invented the low-pressure liquefied circulation process with efficient turbo-expander, is equally to be separated air by twin-stage rectificating method.
Air separation technology belongs to the category of field of chemical engineering, and be the important branch of field of chemical engineering, air separation has certain particularity, in traditional air separation process, owing to also there is micro-moisture, carbon dioxide and hydrocarbon in air, in order to remove these objectionable impurities, have to carry out with air separation in ice chest simultaneously, once removed moisture and partial CO 2 by freezing process at reversible heat exchanger in the past, moisture and carbon dioxide can block heat exchanger channel, pipeline, valve, column plate aperture with solid state existence, acetylene and hydrocarbon are then dissolved in liquid air, when oxygen content in liquid air is too high, acetylene and hydrocarbon are also concentrated simultaneously, and be present in liquid air to know from experience with the oxygenated fluid of high concentration with solid state and cause Chemical explosion, therefore in pressure column, liquid air oxygen content can not raise too high, general about 36%, need not arrange stripping section with regard to this pressure column only has the rectifying of rectifying section separation just can reach this purity, again by the acetylene in liquid air adsorber removing liquid air and other hydrocarbons, comparatively clean liquid air carries out rectifying again at lower pressure column, the safe operation that there is serious threat air separation plant of objectionable impurities, become the principal contradiction that pressure column is separated air, therefore objectionable impurities is present in liquid air and makes pressure column arrange stripping section, is giving full play to of restraining pressure tower rectifying potentiality, and traditional air distillation process must adopt twin-stage rectificating method to be separated air to produce oxygen nitrogen and argon product.
Argon in air separation plant is dissolved in the liquid air of pressure tower reactor usually, therefore wish that the argon that pressure tower top liquid nitrogen is taken away is more few better, in order to higher recovery rate can be had, liquid nitrogen containing oxygen remain on less than 1% and liquid air containing oxygen about 36%, when liquid air reaches more than 41% containing oxygen, then oxygen-free in liquid nitrogen, but containing a large amount of argons in liquid nitrogen, be unfavorable for the extraction of lower pressure column argon; Therefore the separation of oxygen nitrogen and argon must arrange in a lower pressure column on pressure column top and carry out.
Traditional single-stage rectifying device only can produce the pure gas of oxygen or nitrogen, and can not carry argon.
Traditional middle pressure air separation plant due to the expanded air temperature entering pressure column high, the available energy that expanding gas obtains is low, and the cold of device is restricted.
Traditional low pressure air separation plant is higher due to the expanded air temperature entering lower pressure column, has a strong impact on the separating effect of lower pressure column oxygen nitrogen and argon, and therefore an empty point lower pressure column must design very high, and metal material use amount is large; Or between expansion nitrogen and main heat exchanger heat-exchange gas, heat transfer temperature difference is comparatively large, and the available energy making expanding gas obtain reduces greatly, and expansion tolerance all can not be too many, and the cold of device is restricted.
Traditional rectifying column makes tower body low-temperature receiver constant cryogenic liquid usually, or with the form of condenser/evaporator with constant pressure differential, form the constant temperature difference, produce constant phegma, as the low temperature liquid nitrogen that pressure tower top is carried to low pressure tower top, the condenser/evaporator of lower pressure column and pressure column centre, forms phegma and uprising gas carries out caloic exchange, and argon and oxygen in uprising gas are condensed; In traditional rectifying tower, each section of liquid-gas ratio is constant, and because the condensation temperature of liquid oxygen is higher, the operating pressure of pressure column is also higher, and therefore the energy consumption of air separation plant is larger.
Last problem is: because the rectifying column in traditional process all adopted the version of sieve plate to configure in the past, many decades as of late have employed structured packing, but in rectifying column, rectifying goes out the pure nitrogen gas of tower after being separated to air, the low temperature available energy of pure liquid nitrogen, not pure nitrogen gas all cannot make full use of! In any case therefore organize the flow process of single-stage tower, forever can't resolve the cold problem of rectifying column!
Described in indulging above: in traditional process, the version of rectifying column has not adapted to the sky point flow process of single rectification column!
" Principles of Chemical Engineering " are pointed out: the distillation process of Multi component should have a complete rectifying column, complete rectifying column should comprise rectifying section and stripping section, such rectifying column a bi-component mixture continuously, high-purity can be separated into light, weigh two components; For being separated N number of Multi component then by the rectifying separation process with N-1 single rectification column, to obtain all products.Obviously one-hundred-year history so far from traditional air separation equipment is born from its, because scientific and technological level was flourishing not enough at that time, cannot follow the distillation process of " Principles of Chemical Engineering ".
Air separation belongs to the process that oxygen nitrogen and argon three component is separated, and according to the three components of " Principles of Chemical Engineering " from principle, namely can reach the object that rectifying is separated, therefore completely likely realize the unification of both distillation processes by two complete single rectification columns.
After air separation plant adopts normal temperature molecular sieve adsorption principle, objectionable impurities in raw air such as the hydrocarbons such as moisture content, carbon dioxide and acetylene are substantially eliminated the sixth of the twelve Earthly Branches before entering ice chest, substantially eliminate the principal contradiction of serious threat air separation plant safe operation, therefore a single rectification column is completely likely adopted to be separated air, stripping section and rectifying section are set in tower, oxygen content in liquid air is significantly improved, significantly reduces to realize air separation plant energy consumption.
Summary of the invention
The present invention proposes a kind of air separating method of single-stage rectifying device, is applicable to produce the liquid plant containing oxygen 99.5% liquid oxygen product on a large scale; Can also produce containing oxygen is 10ppm ~ 3ppm purity nitrogen product simultaneously; Set up and carry argon column and produce straight argon product, all have high recovery rate to oxygen, nitrogen, argon; Make expansion gas after applying the compression of impure nitrogen circulation, in application of cold temperature liquor pump, compression liquid oxygen, liquid nitrogen produce pressure oxygen nitrogen product; Have employed the completely new approach being built into rectifying column with heat exchanger; The advantages such as energy consumption of the present invention is extremely low, and metal material consumption is few.
1. rectifying device is made up of heat exchanger package, rectifying column and expander system: rectifying column is made up of rectifying section, stripping section and bottom reboiler; Apply the compression of impure nitrogen circulation to make expansion gas and enter the low-temperature receiver that tower made by rectifying column; The thermal source that oxygen enriched liquid in tower reactor made by reboiler is entered after applied compression raw air and the cryogenic oxygen heating liquid vaporization compressed by cryogenic liquid pump; Set up and carry argon column and produce smart argon.
2. rectifying column rectifying section and stripping section are made up of some heat exchangers; Pure nitrogen gas separated after passing into out tower, not pure nitrogen gas enter in the heat exchanger set respective channel set by rectifying column from top to bottom again, heat exchange is carried out with the upflowing vapor in heat exchangers in towers air duct, oxygen in rising steam and argon reduce according to constant temperature and carry out continuous rectification and to be separated and by continuous condensation, can obtain purity nitrogen product at rectifying column top heat exchanger air duct, divided gas flow is gone out tower by after uprising gas re-heat in heat exchanger package.
3. the sixth of the twelve Earthly Branches is by the compression raw air after dehydrater removing moisture and the purification of normal temperature molecular sieve adsorber, after main heat exchanger cooling, enter the heated air that low-temperature liquid oxygen made by tower reactor reboiler, in tower reactor, low-temperature liquid oxygen is heated the cooled liquefaction of raw air while rear oxygen content improves.
4. converge with by-passing part raw air after the raw air of cooled liquefaction goes out tower, the pressure air passage entering rectifying column stripping section heat exchanger is from bottom to top interior excessively cold by the divided gas flow cooling liquid in heat exchanger cooled gas path, cuts down the decompression air rectifying passage entered in the middle part of rectifying column again carry out rectifying separation after going out stripping section through decompression; Namely the heat exchanger section arranged between tower bottom of rectifying tower and raw air porch claims stripping section.
5. obtain the part low-temperature liquid oxygen containing oxygen 99.5% from tower bottom of rectifying tower, after being compressed to by cryogenic liquid pump the critical liquefaction pressure of cryogenic liquid be not less than in pressure column tower reactor corresponding to fluid temperature, vaporizing to through heat exchanger re-heats such as main heat exchangers to be not less than in pressure tower reactor after fluid temperature, enter the thermal source that tower reactor cryogenic liquid made by tower reactor reboiler, after cryogenic liquid cooling fluid dissolves tower, to normal temperature, make pressure oxygen product through heat exchanger package re-heat vaporization; Draw from rectifying column bottom and after main heat exchanger re-heat to normal temperature, go out device containing the cryogenic oxygen of oxygen 99.5% and make Low Pressure Oxygen gas product.
6. after the part low temperature liquid nitrogen obtained from rectifying column tower top goes out tower, be compressed to certain pressure by cryogenic liquid pump, enter again from top to bottom after being gone out tower by the upflowing vapor re-heat in air duct in the heat exchanger channel set by rectifying column, after main heat exchanger re-heat to normal temperature, make pressure nitrogen gas product.
7. after in the heat exchanger air separation passage of raw air in tower, rectifying is separated, the not pure nitrogen gas of drawing in rectifier heat exchanger air separation passage in the heat exchanger package respective channel of Ta Nei and device re-heat to normal temperature, supercharging in supercharger is entered after recycle compressor compression, pressurization gas enters decompressor and makes adiabatic expansion after heat exchanger package is cooled to uniform temperature, and expansion nitrogen then enters in tower and goes out tower in the set impure channel of nitrogen of heat exchanger with after the uprising gas re-heat in heat exchangers in towers air separation passage.
8. introducing expansion nitrogen circulation multiplying power concept N, require expansion nitrogen circulation multiplying power N=A/B > 1, by extracting the not pure nitrogen gas of device to increase expansion tolerance, obtaining rectifying column institute chilling requirement.
9. carry argon column to be made up of heat exchanger; Pass into the argon fraction gas dividing the stripping section argon enrichment region set by rectifying column raw material bottom to draw from sky to enter and carry argon column bottom and make unstrpped gas; Pass into expansion nitrogen or separated pure nitrogen gas or non-pure nitrogen gas or impure liquid nitrogen after passing into out tower, enter in the heat exchanger package respective channel carried set by argon column from top to bottom again, heat exchange is carried out with the argon fraction steam in tower inside heat exchanger passage, oxygen in rising steam reduces according to constant temperature and carries out continuous rectification separation, oxygen in steam is by continuous condensation, can obtain straight argon product carrying argon column top, phegma still returns in the stripping section of empty point rectifying column.
10. between rectifying column and the heat exchanger carrying set by argon column, be provided with column plate section or packing section, long heat exchanger can be divided into some heat exchangers, and and column plate section or packing section interval arrange, for preventing the long bias current causing separated gas of heat exchanger.
Accompanying drawing explanation
The example of the air separation equipment, method of Fig. 1 (a) (b) a kind of single-stage rectifying device.
Fig. 2 (a) (b) a kind of single-stage rectifying device is set up and is carried the air separating method example that straight argon produced by argon column
Detailed description of the invention
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail:
The example of the air separation equipment, method of Fig. 1 (a) (b) a kind of single-stage rectifying device.
The example of the air separating method of a kind of single-stage rectifying device of Fig. 1 (a)
The compression raw air being removed moisture, carbon dioxide and hydrocarbon the sixth of the twelve Earthly Branches by pipeline 1 after main heat exchanger 2 cools, all or part of raw air by pipeline 3, cut down door 4, pipeline 5 enters the thermal source making tower reactor low-temperature liquid oxygen in rectifying column 12 tower reactor reboiler 13, enter the cooled liquefaction of raw air of reboiler 13, low-temperature liquid oxygen simultaneously in tower reactor is heated, and the oxygen content in liquid improves rapidly; After the cooled raw air liquefied goes out rectifying column 12, after subcooler 7 is backflowed cooling gaseous fluid after pipeline 8, pressure-reducing valve 9 reduce pressure and lower the temperature, enter in the middle part of rectifying column 12 through pipeline 10 and make unstrpped gas; When there being part material gas bypass, bypass raw air, after cutting down door 15, pipeline 16 and another part raw air and converging, enters in the middle part of rectifying column 12 and carries out rectifying separation after subcooler 7 cooling liquid decompression; The stripping section arranged in the rectifying column 12 of bottom, raw air porch and between tower reactor and sequence number 12a.
Stream of the present invention is: through pipeline 11 after the raw air of the liquefaction raw air and bypass that go out reboiler 13 converges, enter from bottom to top further mistake in the pressure heat exchanger air duct in tower set by stripping section cold after go out stripping section, to enter in the air duct of rectifying heat exchangers in towers through pipeline 10 after 14 decompressions are cut down in decompression and carry out rectifying separation.
Raw air in the air duct of heat exchangers in towers rectifying be separated after, drawing containing oxygen from rectifying column 12 tower reactor is that 99.5% part low-temperature liquid oxygen is through pipeline 17, after cryogenic liquid pump 18 is compressed to the critical liquefaction pressure of liquid oxygen be not less than in pressure column tower reactor corresponding to fluid temperature, through pipeline 19, main heat exchanger 2 re-heat vaporization is to uniform temperature, through pipeline 20, heat exchanger 21 to be cooled to be not less than in pressure tower reactor after fluid temperature, heated air is made in the reboiler 13 that pipeline 22 enters bottom pressure column 12, gas by cryogenic liquid cooling liquid in reboiler 13 through pipeline 23, after main heat exchanger 2 re-heat to normal temperature, drawn by pipeline 24 and be used as pressure oxygen product and cut down door 28 and make adjustments flow, can obtain from pipeline 17 and account for the low-temperature liquid oxygen product (not drawing figure) that oxygen product total amount is not less than 20%, from rectifying column 12a bottom extension containing oxygen be 99.5% low pressure gas oxygen after pipeline 25, main heat exchanger 2 re-heat to normal temperature, obtain low oxygen through pipeline 26.
From the air duct of rectifying column 12 rectifying section heat exchanger A draw oxygen content not higher than 4% not pure nitrogen gas through pipeline 30, cut down door 31, pipeline 32, subcooler 7, pipeline 33, through pipeline 34 after main heat exchanger 2 re-heat to normal temperature, after circulating nitrogen gas compressor 35 compresses after supercharger 36 supercharging, enter after main heat exchanger 2 cooling through pipeline 37, through pipeline 38, after heat exchanger 20 re-heat, adiabatic expansion is entered in decompressor 40 to 0.125Mpa ~ 0.135Mpa pressure through pipeline 39, low-temperature receiver is made in the impure channel of nitrogen being entered tower inside heat exchanger A by pipeline 41, gas is carried out heat exchange by the steam channel that upflowing vapor is set in heat exchanger A, pure nitrogen gas is not gone out rectifying column 12 through pipeline 42 after re-heat, main heat exchanger 2 re-heat is to normal temperature, device is gone out through cutting down door 43.
Stream of the present invention is that the not pure nitrogen gas of drawing from the air duct of the rectifying section heat exchanger of rectifying column 12 cuts down 48 through decompression and passes in the not purity nitrogen passage of heat exchanger A set in tower, from top to bottom by the upflowing vapor institute re-heat in heat exchangers in towers air duct, draw from the impure channel of nitrogen of stripping section 12a heat exchanger, draw through pipeline 49 and enter in pipeline 33; Supplementing through pipeline 34 by cutting down door 44 or to regulate expansion tolerance, regulating temperature into decompressor 40 gas by cutting down door 58.
In tower, upflowing vapor is in the air duct of heat exchanger A, the cold that provides by low temperature nitrogen passage carry out continuous rectification separation from top to bottom, oxygen in upflowing vapor and argon are along with temperature reduction is by continuous condensation separation, traditional stream is that obtaining nitrogenous from rectifying tower top is 10ppm ~ 3ppm low-pressure nitrogen, by pipeline 50, cut down door 51, pipeline 52, heat exchanger 7 re-heat after, after pipeline 53, main heat exchanger 2 re-heat, go out device again, low-pressure nitrogen product can be obtained through pipeline 54.
Stream of the present invention is that low temperature nitrogen that the air duct pushing up heat exchanger from rectifying column 12 is drawn cuts down 55 through decompression and to enter in tower in the channel of nitrogen of set heat exchanger A, from top to bottom by the upflowing vapor re-heat in heat exchanger A air duct, at the bottom of rectifying column, heat exchanger channel of nitrogen is drawn, and enters in pipeline 53 through pipeline 56.
Guaranteeing under the normal prerequisite of rectifying operating mode, traditional stream draws the pure liquid nitrogen of a small amount of low temperature through pipeline 60 in rectifying tower top liquid bath, through cryogenic liquid pump 61 be compressed to after certain pressure through pipeline 62, cut down door 63, pipeline 64, subcooler 7 re-heat vaporization after after pipeline 65, main heat exchanger 2 re-heat to normal temperature, go out device through pipeline 66 make pressure nitrogen gas product; Part low temperature liquid nitrogen (not drawing figure) can be obtained from pipeline 62.
Stream of the present invention be by the low temperature liquid nitrogen with pressure after low temperature compression in the pressure liquid nitrogen passage that pipeline 55 enters the heat exchanger A set by tower, gone out rectifying column stripping section 12a by after the upflowing vapor re-heat of heat exchanger air duct from top to bottom, enter in pipeline 65 for 68 times through pipeline.
The present invention is considered as a heat exchanger the rectifying section of whole rectifying column and stripping section, and supposition only has two passages of cooling duct and air separation passage, guarantee that rectifying operating mode is normally run; First guarantee there is a fixed difference difference between two passages; Next guarantees that the pressure of air separation passage is higher than the pressure of cooled gas path, general refrigeration ability that gas produces must be greater than total amount of heat that rising releases that the 3rd guarantees to backflow.
Rectifying operating mode in order to ensure heat exchanger is normally run, by above-mentioned condition: when to get the temperature difference be 2.5K ~ 3K, not pure nitrogen gas in expansion channel of nitrogen containing oxygen not higher than 4%, pressure is when being 0.125Mpa, then rectifying tower top air separation channel pressure is about 0.155Mpa ~ 0.165Mpa; Get when entering that in unstrpped gas and tower reactor that reboiler 13 is thermal source, cryogenic liquid mean temperature difference gets 2.0k, an empty point tower bottom of rectifying tower operating pressure is about 0.165Mpa ~ 0.185Mpa; The minimum liquefaction pressure of corresponding raw air is about 0.475Mpa ~ 0.52Mpa.
Divide the stripping section 12a set by rectifying column 12 raw air inlet duct 10 bottom to be made up of heat exchange heat from sky, draw one argon fraction gas from the air duct argon enrichment region of heat exchanger, draw through pipeline 103 and make unstrpped gas; Its phegma is passed back into by pipeline 104 in the air duct of the stripping section 12a heat exchanger of empty point rectifying column 12.
The example of the air separating method of a kind of single-stage rectifying device of Fig. 1 (b)
Compared with Fig. 1 (a), retain stream of the present invention, peeled off pipeline in traditional process, cut down door and equipment, as subcooler 7 etc., described the main difference feature of the present invention and traditional process.
In a word, the present invention pass through obtained expansion not purity nitrogen cryogenic gas make major refrigeration, divided gas flow that rectifying column obtains and low temperature pure nitrogen gas and not pure nitrogen gas etc. make auxiliary cold source; The rising steam that above-mentioned gas passes in rectifying column in set heat exchanger passages and in another passage of heat exchanger from top to bottom carries out heat exchange, rising steam is provided cold continuous condensation by the low temperature gas that backflows, therefore the liquid-vapour ratio in same rectifying section is not constant, but with the backflow of liquid, its liquid-vapour ratio constantly increases; Because temperature is top-down, constantly from cold heating, therefore the phegma of rectifying section and stripping section is from top to down in continuous increase, also to meet in rectifying section and stripping section air oxygen separating from top to down in the rectifying rule constantly increasing vapor liquid equilibrium; For uprising gas: it is a condenser that the air of whole rectifying section and stripping section heats up in a steamer passage, when only containing cryogenic liquid in refrigerating gas, just there is the function of condenser/evaporator at top heat exchanger A; For preventing the long bias current causing gas of heat exchanger, some heat exchangers can be divided into and and column plate section or packing section interval arrange.
In rectifying column of the present invention, in rectifying section and stripping section, each section of liquid-vapour ratio and g/G are not steady state values, but in same rectifying section, (in fact only refer in heat exchanger in upflowing vapor passage rectifying condensation process) liquid-vapour ratio g/G increases from top to bottom gradually, changes the pattern of traditional process rectifying.
The present invention supplements expansion tolerance by the not pure nitrogen gas introducing out device, introduce expansion nitrogen circulation multiplying power concept N, if the expansion nitrogen amount of device is A, when going out device to be separated impure nitrogen amount be B, i.e. expansion nitrogen circulation multiplying power N=A/B, the N < 1 of usual device, require expansion nitrogen circulation multiplying power N=A/B > 1-in theory, circulating ratio N should be less than 2.
The present invention, the rectifying clastotype adopting column plate or packing section in traditional rectifying column, changes the rectifying clastotype of adopting heat exchanger into; Therefore traditional rectifying pattern is revolutionized.
B district between the separated gas passage of heat exchanger A set in tower arranges column plate section or packing section to increase rectification zone, prevents the generation of the Biased flow phenomenon of each heat exchanger uprising gas and down-flowing liquid.
The air duct of rectifying section of the present invention and stripping section becomes the condenser of rising steam, as long as therefore expand cryogenic gas amount in corresponding increase expansion channel of nitrogen, or make to have in expansion nitrogen certain moisture content and suitable raising refrigerating gas and the interchannel temperature difference of air separation, all be conducive to the intensity improving rectifying column cold, improve the rectification efficiency of air duct and obtaining of low temperature liquid nitrogen, be conducive to the shortening of rectifying column height; The present invention need not arrange condenser/evaporator and produce constant phegma, or maintains the normal rectifying operating mode of tower body with constant cryogenic liquid.
Fig. 2 (a) (b) a kind of single-stage rectifying device is set up and is carried the air separating method example that straight argon produced by argon column
Fig. 2 (a) is provided with Argon recovery subsystem on the basis of Fig. 1 stream, carries argon column 100 and is made up of two heat exchanger A, sequence number 101, sequence number 102, divide the argon enrichment region the heat exchanger air duct set by rectifying column 12 raw air inlet duct 10 bottom stripping section 12a to draw one argon fraction gas from sky, enter through pipeline 103 and carry argon column 100 bottom and make unstrpped gas, in the argon steam channel that argon fraction gas enters heat exchanger A with empty point rectifying column 12 extension cryogenic nitrogen gas through cutting down door 105, pipeline 106 enters in the purity nitrogen passage carried set by argon column 100 heat exchanger A and makes refrigerating gas, go out to carry heat exchanger A at the bottom of argon column after re-heat, enter in pipeline 53 through pipeline 107, or the part be separated in air separation column heat exchanger not pure nitrogen gas through pipeline 108, cut down door 109, pipeline 110 enters the channel of nitrogen carrying argon column heat exchanger A and makes low-temperature receiver, go out to carry argon column heat exchanger after re-heat and enter in pipeline 33 through pipeline 111, or from pipeline 41 extension expanding gas through cutting down door 112, pipeline 113 enters in the not purity nitrogen passage carried set by argon column 100 heat exchanger A and makes refrigerating gas, going out to carry argon column heat exchanger after re-heat enters in pipeline 42 through pipeline 114, enter in the purity nitrogen passage carried set by argon column 100 heat exchanger A, the oxygen carried in argon column in Argon fraction gas is condensed, condensed phegma is passed back in the air duct of the stripping section 12a heat exchanger of empty point rectifying column 12 by pipeline 104, straight argon product can be obtained through pipeline 118 from heat exchanger 101 bottom, 119 discharges are cut down through decompression from the on-condensible gas in the ar gas passage carrying argon column 100 top heat exchanger.
Fig. 2 (b) and Fig. 2 (a) are unlike dividing the impure liquid nitrogen of liquid bath extension of rectifying column 12 top heat exchanger air separation passage through pipeline 69 from sky, cut down door 114, pipeline 115 enters the low-temperature receiver that the heat exchanger A channel of nitrogen carried set by argon column 100 carries argon column, oxygen in condensation argon fraction passage in argon fraction gas, gas after re-heat enters in pipeline 53 through pipeline 116, or divide rectifying column 12 extension cryogenic nitrogen gas through cutting down door 105 from sky, pipeline 106 enters in the purity nitrogen passage carried set by argon column 100 heat exchanger A and makes refrigerating gas, going out to carry argon column heat exchanger after re-heat enters in pipeline 53 through pipeline 107, the oxygen carried in argon column argon passage in Argon fraction gas is condensed, condensed phegma passed back into by pipeline 104 air of the heat exchanger of the stripping section 12a of empty point of rectifying column 12 logical in, straight argon product can be obtained from heat exchanger 101T bottom argon passage, draw through pipeline 118, discharge on-condensible gas and cut down 119 through decompression from carrying argon column 100 top and enter in the passage carried set by argon column 100 heat exchanger A and make low-temperature receiver, drawn by pipeline 120 after re-heat.
The cryogenic gas in argon flow process of carrying of Fig. 2 (a) (b) is expansion nitrogen body or from the isolated pure nitrogen gas of king-tower, not pure nitrogen gas, expansion nitrogen and low temperature liquid nitrogen, flow process can select above-mentioned source of the gas to carry the low-temperature receiver of argon column according to the operation conditions of device.
Claims (10)
1. rectifying device is made up of heat exchanger package, rectifying column and expander system: rectifying column is made up of rectifying section, stripping section and bottom reboiler; Apply the compression of impure nitrogen circulation to make expansion gas and enter the low-temperature receiver that tower made by rectifying column; The thermal source that oxygen enriched liquid in tower reactor made by reboiler is entered after applied compression raw air and the cryogenic oxygen heating liquid vaporization compressed by cryogenic liquid pump; Set up and carry argon column and produce smart argon.
2. rectifying column rectifying section and stripping section are made up of some heat exchangers; Pure nitrogen gas separated after passing into out tower, not pure nitrogen gas enter in the heat exchanger set respective channel set by rectifying column from top to bottom again, heat exchange is carried out with the upflowing vapor in heat exchangers in towers air duct, oxygen in rising steam and argon reduce according to constant temperature and carry out continuous rectification and to be separated and by continuous condensation, can obtain purity nitrogen product at rectifying column top heat exchanger air duct, divided gas flow is gone out tower by after uprising gas re-heat in heat exchanger package.
3. the sixth of the twelve Earthly Branches is by the compression raw air after dehydrater removing moisture and the purification of normal temperature molecular sieve adsorber, after main heat exchanger cooling, enter the heated air that low-temperature liquid oxygen made by tower reactor reboiler, in tower reactor, low-temperature liquid oxygen is heated the cooled liquefaction of raw air while rear oxygen content improves.
4. converge with by-passing part raw air after the raw air of cooled liquefaction goes out tower, the pressure air passage entering rectifying column stripping section heat exchanger is from bottom to top interior excessively cold by the divided gas flow cooling liquid in heat exchanger cooled gas path, cuts down the decompression air rectifying passage entered in the middle part of rectifying column again carry out rectifying separation after going out stripping section through decompression; Namely the heat exchanger section arranged between tower bottom of rectifying tower and raw air porch claims stripping section.
5. obtain the part low-temperature liquid oxygen containing oxygen 99.5% from tower bottom of rectifying tower, after being compressed to by cryogenic liquid pump the critical liquefaction pressure of cryogenic liquid be not less than in pressure column tower reactor corresponding to fluid temperature, vaporizing to through heat exchanger re-heats such as main heat exchangers to be not less than in pressure tower reactor after fluid temperature, enter the thermal source that tower reactor cryogenic liquid made by tower reactor reboiler, after cryogenic liquid cooling fluid dissolves tower, to normal temperature, make pressure oxygen product through heat exchanger package re-heat vaporization; Draw from rectifying column bottom and after main heat exchanger re-heat to normal temperature, go out device containing the cryogenic oxygen of oxygen 99.5% and make Low Pressure Oxygen gas product.
6. after the part low temperature liquid nitrogen obtained from rectifying column tower top goes out tower, be compressed to certain pressure by cryogenic liquid pump, enter again from top to bottom after being gone out tower by the upflowing vapor re-heat in air duct in the heat exchanger channel set by rectifying column, after main heat exchanger re-heat to normal temperature, make pressure nitrogen gas product.
7. after in the heat exchanger air separation passage of raw air in tower, rectifying is separated, the not pure nitrogen gas of drawing in rectifier heat exchanger air separation passage in the heat exchanger package respective channel of Ta Nei and device re-heat to normal temperature, supercharging in supercharger is entered after recycle compressor compression, pressurization gas enters decompressor and makes adiabatic expansion after heat exchanger package is cooled to uniform temperature, and expansion nitrogen then enters in tower and goes out tower in the set impure channel of nitrogen of heat exchanger with after the uprising gas re-heat in heat exchangers in towers air separation passage.
8. introducing expansion nitrogen circulation multiplying power concept N, require expansion nitrogen circulation multiplying power N=A/B > 1, by extracting the not pure nitrogen gas of device to increase expansion tolerance, obtaining rectifying column institute chilling requirement.
9. carry argon column to be made up of heat exchanger; Pass into the argon fraction gas dividing the stripping section argon enrichment region set by rectifying column raw material bottom to draw from sky to enter and carry argon column bottom and make unstrpped gas; Pass into expansion nitrogen or separated pure nitrogen gas or non-pure nitrogen gas or impure liquid nitrogen after passing into out tower, enter in the heat exchanger package respective channel carried set by argon column from top to bottom again, heat exchange is carried out with the argon fraction steam in tower inside heat exchanger passage, oxygen in rising steam reduces according to constant temperature and carries out continuous rectification separation, oxygen in steam is by continuous condensation, can obtain straight argon product carrying argon column top, phegma still returns in the stripping section of empty point rectifying column.
10. between rectifying column and the heat exchanger carrying set by argon column, be provided with column plate section or packing section, long heat exchanger can be divided into some heat exchangers, and and column plate section or packing section interval arrange, for preventing the long bias current causing separated gas of heat exchanger.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108224900A (en) * | 2018-01-24 | 2018-06-29 | 北京拓首能源科技股份有限公司 | A kind of oxygen nitrogen and argon piece-rate system using cold energy of liquefied natural gas |
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| US4606745A (en) * | 1984-05-30 | 1986-08-19 | Nippon Sanso Kabushiki Kaisha | Condenser-evaporator for large air separation plant |
| CN2057739U (en) * | 1989-05-13 | 1990-05-30 | 杭州制氧机厂 | Condensed evaporator for large hollow separator |
| CN1076269A (en) * | 1992-03-12 | 1993-09-15 | 孙克澄 | Air separating method and equipment |
| CN103629894A (en) * | 2012-08-22 | 2014-03-12 | 孙克锟 | Air separation method of single-stage distillation device |
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| US4606745A (en) * | 1984-05-30 | 1986-08-19 | Nippon Sanso Kabushiki Kaisha | Condenser-evaporator for large air separation plant |
| CN2057739U (en) * | 1989-05-13 | 1990-05-30 | 杭州制氧机厂 | Condensed evaporator for large hollow separator |
| CN1076269A (en) * | 1992-03-12 | 1993-09-15 | 孙克澄 | Air separating method and equipment |
| CN103629894A (en) * | 2012-08-22 | 2014-03-12 | 孙克锟 | Air separation method of single-stage distillation device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108224900A (en) * | 2018-01-24 | 2018-06-29 | 北京拓首能源科技股份有限公司 | A kind of oxygen nitrogen and argon piece-rate system using cold energy of liquefied natural gas |
| CN108224900B (en) * | 2018-01-24 | 2024-01-09 | 北京拓首能源科技股份有限公司 | Oxygen-nitrogen-argon separation system utilizing liquefied natural gas cold energy |
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